A Criterion for Comparing Measurement Results and Determining Conformity with Specifications

In this paper a new criterion for comparing measurement results and determining conformity with specifications is proposed, which essentially is a strategy of estimating the empirical relationships of objects. Comparing with traditional methods given in GUM: 2008 and ISO 14253-1, this criterion improves the resolution of comparison by reducing the sizes of the coverage intervals to be compared. Interval order (a binary relation) is used for comparing the coverage intervals of the measurand and represents the empirical relations. The systematic effects of measurement are classified into two types: monotonic and non-monotonic effects, so that, without correcting the monotonic effects, a biased measurand can be specified to represent the empirical relations. Thereby the uncertainty components arising from the monotonic effects can be removed from the combined uncertainty. A strategy is given for determining the relationships among measurement results and specification limits. An example is given to demonstrate the application of the criterion

Relational Structure of Measurement with Application on Specification of Freeform Surface

A contradiction is shown in this paper that, for contact surface measurement, if a measured surface profile is exactly coincident with the USL (upper specification limit), the measured result may still be out of specification. To understand and avoid this contradiction, a relational construction of measurement is proposed bases on the representational measurement theory. By observing the connection between measurement and inverse problem, measurement is modeled as a mapping from the preordered set of measurands (objects to be measured) to the partially ordered set of measured values. Thereby, a desired property of the specifications limits is derived, and a correction of the USL of surface profile is proposed

Is the U.S. Stock Market Sufficiently Efficient around Hurricanes?

This paper tests the U.S. stock market efficiency around all 18 hurricanes that have hit continental U.S. since 2000. Using an event-study methodology, the study analyzes the effect of those 18 hurricanes on a sample of 60 property-casualty insurance companies before and following the hurricanes’ landfall. The study supports the semi-strong form market efficiency and concludes that market inefficiency only exists during the pre-landfall period. Moreover, a significant negative relationship is found between the wind speed and firms’ risk exposure, which reiterates the market’s ability to differentiate hurricanes by their damaging power and to discriminate P&C insurers by their existence of exposure

Development and Fabrication of Thermally Conductive Polymer Matrix Composite Foams

Advancements in the electronics industry have led to miniaturized components with increased computing power, which resulted in serious heat management issue. Under such technological trend, the development of new multifunctional packaging materials with excellent thermal conductivity and electrical resistivity, which can be used for heat dissipation, is becoming increasingly important. A recent research revealed the possibility of using foaming-induced filler alignment to promote the effective thermal conductivity (keff). In this context, this thesis research aims to develop thermally conductive polymer matrix composite (PMC) foams that can provide a solution to the heat management of new electronic devices. First, an analytical model was constructed to confirm the feasibility of foaming-induced keff enhancement. This model considered filler alignment caused by foaming-induced stress field, and calculated the keff using the concept of thermal resistor network. Second, a comprehensive experimental study was conducted to parametrically reveal the dependency of PMCs keff on foam morphological parameters, including filler size, foam expansion ratio, cell size, and cell population density. Low density polyethylene (LDPE)-hexagonal boron nitride (hBN) composites blown by Expancel microspheres were studied as a case example to prove the concept